It's possible the two problems are related. If you have a blown head gasket, coolant could be leaking into one or more cylinders, making ignition tough to do

. You could check that by seeing of coolant is in your oil. Whoever does your oil change can check that out for you.
On the other hand, the hard starting could be a dying fuel pump, bad gas filter, fuel pressure regulator, or way past dirty injectors, probably a couple of other things.